The present invention relates to an arrangement for biasing radio-frequency (RF) active components, which are formed in a planar structure in accordance with printed circuit techniques on a dielectric support. A power supply circuit applies a direct biasing current to an active RF component, which is arranged in series with a main transmission line 1, via a transmission line section (4) provided between the circuit and the main transmission line. At a point (6), where transmission line section (4) is connected to the main line, the impedance is sufficiently high to prohibit the transmission of the RF signal passing through the main line (1) to the power supply circuit, while allowing the transmission of the direct current produced by said circuit. The arrangement can be used for biasing RF active components such as diodes or transistors, and more specifically field effect transistors formed in a planar structure in accordance with printed circuit techniques on a dielectric support.
U.S. Pat. No. 4,023,125 filed on Oct. 17th, 1975 by General Electric Company, and published May 10th, 1977 discloses circuits for biasing RF components. The circuits comprise a transmission line section having a high impedance at its junction with the main transmission line through which the RF signal is conveyed. In said circuits it is tried to increase the passband by means of a chain of series-connected transmission line segments, which on the one hand results in a comparatively bulky arrangement and on the other hand does not prevent parasitic reflections from becoming increasingly significant with increasing deviation from the resonant frequency of the transmission line section.